Advantages of BMI-for-Age
Provides a reference for adolescents that was not previously available
Consistent with adult standards so can be used continuously from 2 years of age to adulthood
Tracks childhood overweight into adulthood
Notes:
There are several advantages to using BMI-for-age as a screening tool for overweight and underweight. BMI-for-age provides a reference for adolescents that was not previously available. When the 1977 NCHS growth charts were developed, weight-for-height percentiles were provided only for prepubescent girls up to 10 years and for boys up to 11.5 years. Age and stage of sexual maturation are highly related to body fatness. BMI-for-age is the only indicator that allows us to plot a measure of weight and height with age on the same chart. BMI-for-age was not available in the 1977 charts.
Another advantage is that BMI-for-age is the measure that is consistent with the adult index so it can be used continuously from 2 years of age to adulthood.
These characteristics allow us to use the BMI to track body size throughout the life cycle. BMI in childhood is a determinant of adulthood BMI.